A beginners guide to multirotors (written by a beginner)

[Balu]

Did you mount the props the right way (numbers up) and are all four motor rotating in the correct direction?

 

[Mamalemond]

Did you mount the props the right way (numbers up) and are all four motor rotating in the correct direction?

Yes, I believe that I have them going correctly. The two fronts are turning in, the straight out ones are turning out (and even thought they are pointing downward the numbers are up), and my rudder is counter clockwise.

When I connect to Cleanflight and monitor my motors, I see that numbers two and three are not rev-ing evenly. Motor three tends to run about 100 rpms faster. When I increase roll I can make that change and get them even - but they are not quite even to start with. I re-calibrated the escs by arming with the throttle at 100% and then lowering it - that decreased the difference between 2 and 3.

When I put it into angle mode (aux 2) the diference is even greater - ????

When I look at the screen for the TX it seems as though all of my bars are going the right direction and in the right range. I don't know how to dump my settings in Cleanflight - but I will do that if it helps. Most of the settings are default, with the exception of changing my minimum throttle so I could get it to arm.

Jan

 

[Mamalemond]

PS - I am running Cleanflight 1.1.0 setup as a Tricopter (I heard 1.9 was not good for Tri's). Should I use Y4?

 

[Balu]

No, I'm sure Tri is the right. Since a Y4 would not control the tilting servo for the back motor.

But I don't have any experience with the Dragonfly setup or Cleanflight. I hope someone else can chime in here.

 

[RAnst4038]

I searched and found nothing about balancing the chassis.
Don't you have to tweak things to balance the chassis and put an even load on each motor?

 

[Craftydan]

Yes and no.

Balance makes it fly better (much better if it's badly out of balance), but I've seen airframes with horrible balance points with a stable flight.

Josh's Flying Cast was a great example -- the way the cast formed around the frame, the battery only had room aft of CG -- put the balance point half way between the ideal and the rear motors. It flew and held attitude well, was a little squishy in maneuvering but would washout bad in turns. Put the toy raccoon in the hand . . . and flew like a dream. Rock solid in every way:

 

[Mamalemond]

Yes and no.

Balance makes it fly better (much better if it's badly out of balance), but I've seen airframes with horrible balance points with a stable flight.

Josh's Flying Cast was a great example -- the way the cast formed around the frame, the battery only had room aft of CG -- put the balance point half way between the ideal and the rear motors. It flew and held attitude well, was a little squishy in maneuvering but would washout bad in turns. Put the toy raccoon in the hand . . . and flew like a dream. Rock solid in every way:

View attachment 59976

So.... why does my Dragonfly seem to run motors on 3 higher than on 2? When I am in Cleanflight (1.10) it also shows them revving differently? It is worse when I pull the switch for Angle mode. I have calibrated the escs. When I am on the ground it clearly rises on the left side more than the right.

Physically it seems to be pretty balanced - I can put my fingers in the hole at the bottom of the electro-hub and almost balance.

 

[Balu]

The hole doesn't have to be the balancing point. Depending on your setup it can move, but usually only front to back because most copters are symmetric.

Is it possible that the gyros have not been calibrated on a level surface? The flight controller might think it's not level when you put it on the ground.

 

[Mamalemond]

The hole doesn't have to be the balancing point. Depending on your setup it can move, but usually only front to back because most copters are symmetric.

Is it possible that the gyros have not been calibrated on a level surface? The flight controller might think it's not level when you put it on the ground.

I calibrated it while it was sitting on my desk. That is close enough to level that it shouldn't be the problem...

Good thought though

 

[spades in flight]

I need a cheep ESC preferably under $150 any suggestions?

 

[Balu]

I need a cheep ESC preferably under $150 any suggestions?

I'm not sure what you are asking for. Cheap ESCs can be around $10-15?

 

[Richmond2000]

a few NOOB questions
I am "flying" a QX nano with the goal of building a versacopter WITH FPV and "light" racing
this site has bean good in covering ESC props voters ETC but I have "missed" talk on what comes AFTER the basic "crash" build and would like to build my "crash" copter with future-proof upgradeability

ONE shot 125 what is it? - what components NEED its support beyond ESC's
PIDs and tuning again when does this apply and what is being tuned? - is it like the 3 pots on the hobby king controller(KK 2?) but WAY more advanced?
as seen in the H quad build http://flitetest.com/articles/H_Quad_Scratch_Build
what is required to get telematics about batt life / performance ETC

thanks in advance

 

[Balu]

Those are things that go way beyond the "beginners guide", but here you go:

Oneshot125 is a faster communication protocol between flight controller and the ESCs. It allows the FC to send control commands to the ESCs faster, which results in a better performance of the multirotor since it can react quicker to changes.

PIDs is a chapter on its own. Others can explain that a lot better than I can http://blog.oscarliang.net/understanding-pid-for-quadcopter-rc-flight/

For telemetry you need a transmitter / receiver combination with that feature and usually different sensors for all values you want to transfer. There are also on screen displays that write telemetry data into the video signal that is transferred to your goggles/monitor.

 

[Richmond2000]

Those are things that go way beyond the "beginners guide", but here you go:

Oneshot125 is a faster communication protocol between flight controller and the ESCs. It allows the FC to send control commands to the ESCs faster, which results in a better performance of the multirotor since it can react quicker to changes.

PIDs is a chapter on its own. Others can explain that a lot better than I can http://blog.oscarliang.net/understanding-pid-for-quadcopter-rc-flight/

For telemetry you need a transmitter / receiver combination with that feature and usually different sensors for all values you want to transfer. There are also on screen displays that write telemetry data into the video signal that is transferred to your goggles/monitor.

thanks

your link "solved" the PID / programming question - basically I should NOT NEED to play with it and "basic" tuning IF necessary is simple enough - more "P" for more horizon stabilization FORCE to much and oscillation

I was more interested in knowing if PIDs and PROGRAMMING is something I NEED to do for something like a NAZE 32 OR is it to make the flight better when I "grow" into that level of flying

I was worried that ONEshot would actually be a detriment to a NOOB pilot and was wondering if I should buy NON oneshot ESC's
but if it is a high speed comms oneshot would be NOOB "friendly"

it was late when I posted the first time and I should have bean MORE clear I am looking MORE to build a setup that is beginner friendly but WILL work when I grow into it VS having to rebuild with higher performance parts

and was looking at the lumenier mini quad starter pack OR
flitetest's power pack E with a NAZE 32

I have "chosen" the NAZE because the KK inside the versacopter frame does not sound good to me + the NAZE being popular should have better support

 

[shythephotoguy]

Beginners fun

Very complete thread start indeed! But please mention the tons of fun learn how to fly with a cheap mini/micro multirotor. I'm having three Mini H8's now (JJRC/Eachine) with loads of batteries, props and a flash usb dongle. Did't spend more than €50,- and had tons of flying time and fun hacking it.

I'm now building a new frame for my first H8 mini of 6mm plywood.

And my third H8 with stock frame i'm going to flash the software to enable acro flying.

 

[Balu]

It's a nice article. Mine here is a little dated and should probably be updated some time.

 

[badResident]

This is great! Wished I had started with all this help!!

Cheers!

 

[weaverg]

Multirotor motor spacing

Hello,

How important is it that the motors be equally spaced, is their some formula

thanks

 

[Craftydan]

It helps even out the load across the motors and it does reduce some of the slop in the control loops, but for most conditions it's at best the difference between excellent and OK, with the occasional "that feels a little weird" on some of the exaggerated layouts. Most boards can take it and still fly well.

I've seen a handful of motor mixer calculators over the past few years, and a quick google search popped up this one:

https://www.iforce2d.net/mixercalc/

Looks like a nice graphical layout that you can manually enter the distances into the text-box to the right in terms of distance between the motors, with a few common frames to compare against. Pick the firmware you're using and it generates the Command Line info you need.

I'm sure there are others, and the underlying math isn't that hard, but if a calculator can do it, I'll let it do the heavy lifting.

 

[Balu]

I've done an article with some math a while ago:

https://flitetest.com/articles/calculating-the-center-of-thrust-on-multirotors